This module defines a standard interface to break Uniform Resource Locator (URL)
strings up in components (addressing scheme, network location, path etc.), to
combine the components back into a URL string, and to convert a “relative URL”
to an absolute URL given a “base URL.”

Parse a URL into six components, returning a 6-tuple. This corresponds to the
general structure of a URL: scheme://netloc/path;parameters?query#fragment.
Each tuple item is a string, possibly empty. The components are not broken up in
smaller parts (for example, the network location is a single string), and %
escapes are not expanded. The delimiters as shown above are not part of the
result, except for a leading slash in the path component, which is retained if
present. For example:

Following the syntax specifications in RFC 1808, urlparse recognizes
a netloc only if it is properly introduced by ‘//’. Otherwise the
input is presumed to be a relative URL and thus to start with
a path component.

Parse a query string given as a string argument (data of type
application/x-www-form-urlencoded). Data are returned as a
dictionary. The dictionary keys are the unique query variable names and the
values are lists of values for each name.

The optional argument keep_blank_values is a flag indicating whether blank
values in percent-encoded queries should be treated as blank strings. A true value
indicates that blanks should be retained as blank strings. The default false
value indicates that blank values are to be ignored and treated as if they were
not included.

The optional argument strict_parsing is a flag indicating what to do with
parsing errors. If false (the default), errors are silently ignored. If true,
errors raise a ValueError exception.

The optional encoding and errors parameters specify how to decode
percent-encoded sequences into Unicode characters, as accepted by the
bytes.decode() method.

Use the urllib.parse.urlencode() function (with the doseq
parameter set to True) to convert such dictionaries into query
strings.

Parse a query string given as a string argument (data of type
application/x-www-form-urlencoded). Data are returned as a list of
name, value pairs.

The optional argument keep_blank_values is a flag indicating whether blank
values in percent-encoded queries should be treated as blank strings. A true value
indicates that blanks should be retained as blank strings. The default false
value indicates that blank values are to be ignored and treated as if they were
not included.

The optional argument strict_parsing is a flag indicating what to do with
parsing errors. If false (the default), errors are silently ignored. If true,
errors raise a ValueError exception.

The optional encoding and errors parameters specify how to decode
percent-encoded sequences into Unicode characters, as accepted by the
bytes.decode() method.

Construct a URL from a tuple as returned by urlparse(). The parts
argument can be any six-item iterable. This may result in a slightly
different, but equivalent URL, if the URL that was parsed originally had
unnecessary delimiters (for example, a ? with an empty query; the RFC
states that these are equivalent).

This is similar to urlparse(), but does not split the params from the URL.
This should generally be used instead of urlparse() if the more recent URL
syntax allowing parameters to be applied to each segment of the path portion
of the URL (see RFC 2396) is wanted. A separate function is needed to
separate the path segments and parameters. This function returns a 5-tuple:
(addressing scheme, network location, path, query, fragment identifier).

The return value is actually an instance of a subclass of tuple. This
class has the following additional read-only convenience attributes:

Combine the elements of a tuple as returned by urlsplit() into a
complete URL as a string. The parts argument can be any five-item
iterable. This may result in a slightly different, but equivalent URL, if the
URL that was parsed originally had unnecessary delimiters (for example, a ?
with an empty query; the RFC states that these are equivalent).

Construct a full (“absolute”) URL by combining a “base URL” (base) with
another URL (url). Informally, this uses components of the base URL, in
particular the addressing scheme, the network location and (part of) the
path, to provide missing components in the relative URL. For example:

If url contains a fragment identifier, return a modified version of url
with no fragment identifier, and the fragment identifier as a separate
string. If there is no fragment identifier in url, return url unmodified
and an empty string.

The return value is actually an instance of a subclass of tuple. This
class has the following additional read-only convenience attributes:

The URL parsing functions were originally designed to operate on character
strings only. In practice, it is useful to be able to manipulate properly
quoted and encoded URLs as sequences of ASCII bytes. Accordingly, the
URL parsing functions in this module all operate on bytes and
bytearray objects in addition to str objects.

If str data is passed in, the result will also contain only
str data. If bytes or bytearray data is
passed in, the result will contain only bytes data.

To support easier conversion of result objects between str and
bytes, all return values from URL parsing functions provide
either an encode() method (when the result contains str
data) or a decode() method (when the result contains bytes
data). The signatures of these methods match those of the corresponding
str and bytes methods (except that the default encoding
is 'ascii' rather than 'utf-8'). Each produces a value of a
corresponding type that contains either bytes data (for
encode() methods) or str data (for
decode() methods).

Applications that need to operate on potentially improperly quoted URLs
that may contain non-ASCII data will need to do their own decoding from
bytes to characters before invoking the URL parsing methods.

The behaviour described in this section applies only to the URL parsing
functions. The URL quoting functions use their own rules when producing
or consuming byte sequences as detailed in the documentation of the
individual URL quoting functions.

The result objects from the urlparse(), urlsplit() and
urldefrag() functions are subclasses of the tuple type.
These subclasses add the attributes listed in the documentation for
those functions, the encoding and decoding support described in the
previous section, as well as an additional method:

Return the re-combined version of the original URL as a string. This may
differ from the original URL in that the scheme may be normalized to lower
case and empty components may be dropped. Specifically, empty parameters,
queries, and fragment identifiers will be removed.

For urldefrag() results, only empty fragment identifiers will be removed.
For urlsplit() and urlparse() results, all noted changes will be
made to the URL returned by this method.

The result of this method remains unchanged if passed back through the original
parsing function:

The URL quoting functions focus on taking program data and making it safe
for use as URL components by quoting special characters and appropriately
encoding non-ASCII text. They also support reversing these operations to
recreate the original data from the contents of a URL component if that
task isn’t already covered by the URL parsing functions above.

Replace special characters in string using the %xx escape. Letters,
digits, and the characters '_.-' are never quoted. By default, this
function is intended for quoting the path section of URL. The optional safe
parameter specifies additional ASCII characters that should not be quoted
— its default value is '/'.

The optional encoding and errors parameters specify how to deal with
non-ASCII characters, as accepted by the str.encode() method.
encoding defaults to 'utf-8'.
errors defaults to 'strict', meaning unsupported characters raise a
UnicodeEncodeError.
encoding and errors must not be supplied if string is a
bytes, or a TypeError is raised.

Note that quote(string,safe,encoding,errors) is equivalent to
quote_from_bytes(string.encode(encoding,errors),safe).

Like quote(), but also replace spaces by plus signs, as required for
quoting HTML form values when building up a query string to go into a URL.
Plus signs in the original string are escaped unless they are included in
safe. It also does not have safe default to '/'.

Replace %xx escapes by their single-character equivalent.
The optional encoding and errors parameters specify how to decode
percent-encoded sequences into Unicode characters, as accepted by the
bytes.decode() method.

Convert a mapping object or a sequence of two-element tuples, which may
either be a str or a bytes, to a “percent-encoded”
string. If the resultant string is to be used as a data for POST
operation with urlopen() function, then it should be
properly encoded to bytes, otherwise it would result in a TypeError.

The resulting string is a series of key=value pairs separated by '&'
characters, where both key and value are quoted using quote_plus()
above. When a sequence of two-element tuples is used as the query
argument, the first element of each tuple is a key and the second is a
value. The value element in itself can be a sequence and in that case, if
the optional parameter doseq is evaluates to True, individual
key=value pairs separated by '&' are generated for each element of
the value sequence for the key. The order of parameters in the encoded
string will match the order of parameter tuples in the sequence.

When query parameter is a str, the safe, encoding and error
parameters are passed down to quote_plus() for encoding.

To reverse this encoding process, parse_qs() and parse_qsl() are
provided in this module to parse query strings into Python data structures.

Refer to urllib examples to find out how urlencode
method can be used for generating query string for a URL or data for POST.

This is the current standard (STD66). Any changes to urllib.parse module
should conform to this. Certain deviations could be observed, which are
mostly for backward compatibility purposes and for certain de-facto
parsing requirements as commonly observed in major browsers.